Elevator safety apparatus



W. E. BOEHCK.

ELEVATOR SAFETY APPARATUS. APPLICATION FILED AUG-1. 1919.

1,378,944. Patented Ap1i5, 1921.

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J52 0622222" ZMZWM$M llEl TATE FAB WILLIAM EDWARD IBOEHGK, 0E JERSEYCITY, NEW JERSEY ASSIGNOR T0 I:,EV'()1', TOR COMPANY, OF JERSEY GT'IY,NEVI JERSEY, A CORPORATION OF NEW JERSEY.

ELEVATOR SAFETY APPARATUS.

Patented Apr. 5, i921.

Application filed August 1, 1919 Serial No. 314,644,

T 0 all whom it mag concern Be it known that 1, WILLIAM EDWARD Boer-ragacitizen of Germany, residing at Jersey City, in the county of Hudson andtate of New Jersey, have invented certain new and useful Improvements inElevator Safety Apparatus, of which the following is a specification,reference being had to the accompanying drawings.

This invention relates to improvements in safety devices for elevatorsand particularly to improvements in safety devices for tiering machines(otherwise known as portable elevators), the purpose of which devices isto prevent the dropping of the load-carrying platform, in case thehoisting-cable should break; and an object ofthis invention is toprovide a safetydevice of the kind just mentioned, which will be simplein construction, comparatively cheap in manufacture, and eiiicient anddurable in operation and use, and the cost of repairs of which willprove small. Another object of this invention is the provision of meanswhereby. the engagement of the holding cams with the elevator-standardsis prevented or obviated, in case the operator should slacken thehoisting cable sufiiciently when the platform hasbeen lowered so thatthe same rests upon the bottom structure or base of the elevator.

In the drawings illustrating the principle of this invention and thebest mode now known to me of applying that principle, Figure l is anelevation of so much of a tiering machine as is necessary to illustratethis invention; Fig. 2 is a side view, looking in the direction of thearrows in Fig. 1, the view being partly in section on the line 22 ofFig. 1; and Figs. andd are de tails illustrating the toothed r holdingor clutch cam in side and front elevation, respectively.

As isuconventional in structures of this class, the tiering machine isprovided with a pair of uprights or standards a, which are made ofchannel-iron or of steel, as may be preferred. There is one of thesestandards a at each side of thetiering machine; and each standard acomprises a web a fromeach vertical edge of which there projectsinwardly a flange a thereby giving to the standard at its channeledform. The load-receiving platform 6 is (as is shown in Fig. 2)horizontally disposed and is carried,

by the Ushaped lifting-frame or guideframe 0 that consists of a pair ofupright guide-arms c, the lower ends of which are connected by across-beam a". A pair of inclined braces 0* (Fig. 1) joins the latterwith each of the arms 0. When the liftingframec is raised, it carrieswith it the.load-' receivmg platform 6." From the upper end of each arm0, there extends laterally and outwardly a stub-shaft or arbor d,'whichpro ects into the channel of the opposed ma' chine-standard a anduponwhich is rotatably mounted a guideroller e. The flanges a" of themachine-standard to serve as tracks upon. which the guide-roller 6travels. The lower end of each arm or upright 0 of the lifting-frame cis similarly provided with an outwardly and laterally projectingrollershaft d upon which turns a lower guide roller 6' that runs on theflanges a" as tracks in the same manner as does the upper guide-rollere.-

l'iorizontally disposed beneath the rigid cross-bar 0 of thelifting-frame 0 there is a loose hoisting crossbeam f to the front andrear faces of which there are fastened, by means of the ping, the lowerends of a pair of pull-straps or pull-links h, which extend upwardlyfrom. the-loose cross-bar. f and between which lies the rigid cross-bar0 of the load-carrying platform 6. The lower end of .the hoisting-cablei enters between the upper ends of the pull-links hand is formed with aloop i,=through.which and i allowed to descend.

From near the middle of each guide-arm 0", and between theroller-carrying shafts ol, d,

there extends laterally and outwardly a camcarrying shaft In whichprojects into the channel oftlie opposed machine-standard w and uponwhich there is mounted, free to swingga holdingor clutch cam m of. analmost semi-circular shape (Figs. 3 andd). The hole at. through whichpasses the pivot or shaft lc is eccentrically located in the holding-camm, and, from the top of the latter, there extends upwardly an ear m 7formed with a perforation m". The convex face n ofthe cam m is beveledor inclined from one of its edges to the other thereof, in order that,the face a may conform to the bevel or inclination of the opposed faceof the flange a, of the machine-standard a; and; in order to allow forthe inaccuracies or inequalities of the bevel of this opposed face, theface 12 of the cam on is slightly rounded. Ratchet teeth n are formed inthe face 12 for the purpose of increasing the gripping action of the camm, when the latter is thrown against the flange a opposed thereto. Fromthe ends of the loose lifting crossbeam 7, there project horizontallythe lugs f the free ends of which are perforated to receive the lowerends of the Z-shaped linkrods 0. The upper end of each linli-rod o isfitted into the perforation m formed in the ear m of the cam m,- andwhen the loose hoisting'cross-beam moves downwardly with relation to theplatform cross-beam 0", the connecting link-rods 0 transmit the 1110-tion and rock the two holding cams m on their pivots or shafts is, sothat the toothed cam-faces 72 are pressed into clutching engagment withand against-the beveled faces of the flanges a of the machine-standardsa and there results a frictional gripping action of the cams mtherewith. At each side of the machine, there is provided a coilspring79 the lower end of which is attached to the adjacent guide-arm c andthe upper end of which is fastened to that end of the connectingrod 0which enters the ear 0??" of the cam m on that side of the machine (Fig.1). These coil-springs p tend to throw the connecting-rods 0 downwardlyand cause the same promptly to follow any drop of the loose cross-beamrelatively to the fixed cross-beam'c of the platform 2') and thereby toinsure quick action of the clutch-cams m.

The operation of the safety contrivance described hercinhefore may bebriefly set forth as follows and will be readily understood. So long asthe hoisting mechanism of the tiering machine operates normally, thepull of the hoisting-cable i (acting in one direction) and the weight ofthe platform 5 and the load thereon (acting in the opposite direction)hold the two horizontal crossbars 0", f, firmly pressed together and Vmaintain the clutch-cams m in the full-line CII (or inoperative)position shown in Fig. 2, against the tension of the coil-springs When,however, the hoisting-cable breaks, the loose cross-beam f will droprelatively to the rigid or fixed cross-bea1ns a of the platformguide-frame c and will fall away therefrom, the co1l-springs pwillcontract and the holding-cams m will be rocked on their pivots Z4 so asto force their toothed cam-faces n into frictional clutching contactwith the opposed faces of the flanges a of the standards a. The resultof the rubbing of the "toothed faces at of the cams m against theflanges a is that the eccentrically-mounted cams m are given a rollingmotion and theguiderollers c are forced with intense pressure againstthe opposite ;e of the flanged channel-beam a, whereby great frictionalresistance to the downward movement of the platform 6 is produced andthe same is brought to rest and held up, despite the rupture of thehoisting-cable i.

it is to be observed that the cams on are mounted, and therefore act,independently of each other, whereby the stresses produced by the suddenthrowing of the weight of the platform and the load thereon upon thestandards a are distributed between the latter, instead of beingconcentrated upon a single standard, which concentration results inthose cases in which the holding-cams are mounted on a common shaft andhence are compelled to act in unison, and when the structural shapes adiffer slightly from each other in form and dimensions of the channeland its walls, a difference that is practically always to be found inthe structural shapes a as'they are commercially produced and marketed.Due to such slight inequalities, one of the cams at will engage beforethe other; and, if the two cams were mounted on a common shaft, one camwould almost surely come into gripping action, while the other would notengage effectively with the flange a of the guidestandards a, from whichit would result that the standard a upon which the load would be thrownwould be forced to sustain the weight alone or to collapse. Of course,when the collapse of the standard :es place, the disaster that followsis greater by far than if the loaded platform 7) were to drop; liable tooccur, particularly in case the platform Z) is loaded to the capacity ofthe ma- ;hine.

Should the operator permit the hoistingcable 71 to become slack, whilethe platform I) is resting upon the bottom-structure or base 9 of theelevator, the holding-cams m are liable to be thrown into frictionalengagement with the standards ca In order to obviate such engagementunderthe conditions just mentioned, the following arrangement of partsis provided, namely: From the loose lifting cross-beam f, thereextends'or projects downwardly a pair of posts or bolts 7 the lower endsof which are threaded and pass through holes formed in a horizontal bararranged parallel tothe lifting-beam f. The bar 5 is held on the postsor guide-bolts 1 by means of the nuts t that are screwed on theprojecting threaded ends ofthe poster. Mounted on the latter andinterposed between the lifting-beam f and the bar 8, there arecompression-springs it which tend to hold the bar 8 against the nuts "25and, thereand such collapse is veryrest upon the elevator-base 9, thereare the stop-brackets '0. When, therefore, the platform 2) rests uponthe elevator-base g and the hoisting-cable i is slackened, theliftingbeam 7 and the platform-crossbar 0 will nevertheless be found tobe held firmly.

pressed together by the tension of the coilsprings a, the bar 8 bearingupon the stopbrackets q; at this time; and the holdingcams m will bemaintained in their normal or inoperative position. Should thehoisting-cable 2' become slack (as in case of the rupture thereof),while the platform I) is above the elevator-base g and the bar .9 isabove the stop-brackets o, the lifting-beam f, the bar 8, guide-posts rand coil-springs u will, as a unit, fall away from the platform crossbar0', thereby throwing the holdingcams on into frictional engagement withthe faces of the flanges a" of the guide-standards a in the manner andby the means already fully described hereinbefore.

This application is filed as a continuation in part of my pendingapplication, Serial No. 30487 5, filed June 17, 1919.

I claim:

1; Elevator safety apparatus for tiering machines, including a hoistingmechanism; a pair of fixed standards; a load-carrying platform mountedto travel therebetween; platform-guiding rollers arranged to travelalong said standards; a lifting-beam below said platform and supportedby said hoisting mechanism, said lifting-beam being free to movedownwardly relatively to said platform in case said hoisting mechanismceases to support said lifting-beam; cams mounted free to turnindependently of each other and arranged to travel in close proximity tosaid standards; and cam-actuating devices connecting said cams andlifting-beam and arranged to throw said cams into frictional engagementwith said standards when said lifting-beam falls relatively to saidplatform, whereby said platform-guiding rollers are forced intofrictional engagement with said standards and the platform is held fromdropping.

2. Elevator safety apparatus for tiering machines, including a hoistingmechanism;

a pair of fixed standards; a load-barrying platform mounted to traveltherebetween; platform-guiding means arranged to travel along saidstandards; a lifting-beam below i said platform and attached to saidhoisting mechanism, said lifting-beam being free to move downwardlyrelatively to said platform in case said hoisting mechanism ceases tosupport said lifting beam; devices for throwing said platform-guidingmeans into frictional engagement withsaid standards when saidlifting-beam falls relatively to said platform; and mechanism forpreventing the operation of said devices when the platform is supportedotherwise than by the hoisting mechanism.

3. Elevator safety apparatus for tiering machines, including a hoistingcable; a pair of fixed standards; a load-carrying platform mounted totravel therebetween; aliftingbeam below said platform and attached tosaid hoisting cable, said lifting-beam being free to move downwardlyrelatively to said platform in case said cable should become slack;devices for preventing the fall of said platform when said cable becomesslack or ruptures, said devices being thrown into 5 operation by thefall of said lifting-beam; and mechanism for preventing the operation ofsaid devices when the platform is supported otherwise than by thehoisting cable.

4:. Elevator safety apparatus for tiering machines, including a hoistingcable; a pair of fixed standards; a load-carrying platform mounted totravel therebetween; a liftingbeam below said platform and attached tosaid hoisting cable, said lifting-beam being free to move downwardlyrelatively to said platform in case said cable should become slack;devices for preventing the fall of said platform when said cable becomesslack or ruptures, said devices being thrown into operation by the fallof said'lifting-beam; and mechanism for holding said liftingbeam andplatform against separation from each other in case they are supportedotherwise than by said cable.

Signed at Jersey City, New Jersey, in the presence of the twoundersigned witnesses this 23rd day of uly, A. D. 1919..

WILLIAM EDWARD BOEHCK.

Witnesses Hnnwre BonHoK, FERDINAND Manson.

